Exhibit 23

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in the Registration Statements on Form S-8 (Nos. 33-37261, 33-69596, 33-69598, 33-61558, 333-79443, 333-08994, 333-42635, 333-89971, 333-36146, 333-36150 and 333-112527) and Form S-3 (File No. 333-113757) of Southern Union Company of our report dated March 16, 2006 relating to the consolidated financial statements, management’s assessment of the effectiveness of internal control over financial reporting and the effectiveness of internal control over financial reporting, which appears in this Form 10-K.

/s/ PricewaterhouseCoopers LLP

Houston, Texas

March 16, 2006